User Agent Server (Uas) - Yealink SIP-T2xP Administration Manual

method may be the preferred measure when not using an application layer firewall,
application layer firewalls like to know what applications are flowing though which
ports and it is possible using content types of other applications other than the one you
are trying to let through which has been denied.

User agent server (UAS)

UAS is the Server that hosts the application responsible for receiving the SIP requests
from a UAC, and on reception returns a response to the request back to the UAC. The
UAS may issue multiple responses to the UAC, not necessarily a single response.
Communication between UAC and UAS is client/server and peer-to–peer.
Typically, a SIP end point is capable of functioning as both a UAC and a UAS, but it
functions only as one or the other per transaction. Whether the endpoint functions as a
UAC or a UAS depends on the UA that initiates the request.
This section introduces the SIP-T2xP IP phone family. The Yealink SIP-T2xP IP phones are
end points in the overall network topology, which are designed to interoperate with
other compatible equipments including application servers, media servers,
internet-working gateways, voice bridges, and other end points. The SIP-T2xP IP phones
are characterized by a large number of functions, which simplify business
communication with a high standard of security and can work seamlessly with a large
number of SIP PBXs that support SIP .
The SIP-T2xP IP phones provide a powerful and flexible IP communication solution for
Ethernet TCP/IP networks, delivering excellent voice quality. The high-resolution graphic
display supplies content in multiple languages for system status, call history and
directory access. The SIP-T2xP IP phones also support advanced functionalities,
including LDAP , Busy Lamp Field, Shared Call Appearance and Centralized Conference.
The following IP phone models are described:
SIP-T28P

SIP-T26P
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SIP-T22P
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SIP-T20P

The Yealink SIP-T2xP IP phones comply with the SIP standard (RFC 3261), and they can
only be used within a network that supports this type of phone.
For the Yealink SIP-T2xP IP phones to successfully operate as SIP endpoints in your
network, they must meet the following requirements:
A working IP network is established.

Routers are configured for VoIP .

Product Overview
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